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Abstract

PURPOSE: To produce a lead wire excellent in solderability and discoloration resistance by providing an Ag coating layer via an undercoat layer of Ni, Co, Fe, etc., to a Cu core material and applying wiredrawing to the resulting wire at respectively specified drafts while exerting heat treatment between the wiredrawing stages.

CONSTITUTION: An undercoat layer consisting of Ni, Co, Fe, or alloys thereof is provided to a core material in which at least the surface is composed of Cu or Cu alloy. Suitable thickness of the undercoat layer is finally about 0.1-2.0μm. Subsequently, an Ag or Ag alloy coating layer is provided to the above undercoat layer. The thickness of this coating layer is regulated, finally, to about 0.5-5μm, and the above layers are formed by a plating method. Then, wiredrawing is applied to the resulting Ag- coated wire at a draft of ≥30%, preferably about 30-90% and heat treatment is then applied to the above wire at about 500-800°C. Further, the resulting heat-treated Ag- coated wire is subjected to wiredrawing at a draft of ≤15%, preferablit about 5-10%. By this method, the Ag coating layer can be moderately work-hardened, and the lead wire for electronic parts and equipment excellent in solderability and discoloration resistance can be obtained.

COPYRIGHT: (C)1991,JPO&Japio

JP17869189A1989-07-111989-07-11Production of lead wire for electronic parts and equipment
PendingJPH0344453A
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